High density solder tail connector assembly for leadless integrated circuit packages

Abstract

A high density solder tail connector assembly for leadless integrated circuit packages. The plastic connector package includes upper and lower header portions each having a plurality of mating terminal reception channels formed therein. The upper header portion includes probing holes to allow ready testing of integrated circuit packages mounted on the connector assembly. Each channel is designed to receive an inner and an outer type of S-shaped spring-beam contact. Each type of unitary contact includes a contacting portion, a generally S-shaped spring-beam portion, a probe portion, a base portion, and a solder tail or wire-wrap portion. The two types of contacts differ with respect to the location of the solder-tail portion. Each contact is provided with an offset or dog-leg portion adjacent to the solder tail portion which allows the two types of solder tail portions to project in a staggered fashion from the underside of the lower header, thus easing spacing requirements for printed circuit board holes into which the solder tail would be placed. Preloading means formed in the upper header portions insure that all contacts are automatically preloaded when the upper and lower header portions are secured together.

What is claimed is: 
     
       1. A connector assembly for leadless integrated circuit packages comprising: (a) a plurality of complementary pairs of unitary metallic contacts, each of said contacts comprising: (i) an elongated S-shaped spring-beam portion;   (ii) a contacting portion formed on an upper part of said spring-beam portion;   (iii) a preloading tab formed on said upper part of said spring-beam adjacent said contacting area;   (iv) a substantially flat base portion connected to a lower part of said spring-beam portion;   (v) a dog-leg portion formed on said base portion; and   (iv) a downwardly extending tail portion formed on said dog-leg portion, said complementary pairs of contacts differing solely in the location of said dog-leg portion formed on said base portion; and     (b) upper and lower dielectric headers each having a plurality of contact receiving cavities formed therein, said cavities separated by a plurality of intermeshing walls, each said cavity of said lower header including channel means for receiving said contact, and each said cavity of said upper header including contact receiving means and preloading means to bias said contact in a preloaded position when said upper header is fitted over said lower header.   
     
     
       2. The connector assembly of claim 1 wherein said upper header contact receiving means and preloading means includes an opening for receiving said contacting portion of said contacts and a preloading ledge formed adjacent to said contact receiving opening to cooperate with said preloading tab formed on said spring-beam portion of said contacts to controllably bias said spring-beam portion in a preloaded position when said upper header is fitted over said lower header. 
     
     
       3. The connector assembly of claim 1 wherein said spring beam portion of said contacts is formed having a variable cross section. 
     
     
       4. The connector assembly of claim 1 wherein said contacting portion of said spring-beam contacts is formed having an arcuate shape, said contacting portion for contacting terminal pads of a leadless integrated circuit device. 
     
     
       5. The connector assembly of claim 1 wherein said contacts include a probe portion formed on said base portion and projecting upwardly therefrom. 
     
     
       6. The connector assembly of claim 5 wherein said upper header contact receiving cavities each include an opening formed in an upper portion of said upper header cavity for receiving said probe portion of said contacts. 
     
     
       7. The connector assembly of claim 1 wherein said lower header channel means comprises a pair of substantially flat channel portions formed within said lower header contact receiving cavity, said channel portions having a dog-leg shaped ridge formed therebetween to separate said pairs of complementary contacts, each said channel portion including an opening for receiving said tail portion of said contacts. 
     
     
       8. A connector assembly for leadless integrated circuit packages comprising: (a) a plurality of complementary pairs of unitary metallic contacts, each of said contacts comprising: (i) an elongated S-shaped spring-beam portion;   (ii) an arcuate contacting portion formed on a an upper part of said spring-beam;   (iii) a preloading tab formed on said upper part of said spring-beam adjacent said arcuate contacting area;   (iv) a substantially flat base portion connected to a lower part of said spring- beam portion;   (v) a dog-leg portion formed on said base portion;   (vi) a downwardly extending tail portion formed on said dog-leg portion;   (vii) a probe portion formed on said base portion; and   (viii) a locating pin formed on said base portion, said complementary pairs of contacts differing solely in the location of said dog-leg portion formed on said base portion; and     (b) upper and lower dielectric headers each having a plurality of contact receiving cavities formed therein, said cavities separated by a plurality of intermeshing walls, each said cavity of said lower header including channel means for receiving said contacts and a locating opening formed within said channel means for receiving said contact locating pin to securably retain a contact inserted into said channel means, and each said cavity of said upper header including contact receiving means and preloading means to bias said contact in a preloaded portion when said upper header is fitted over said lower header.   
     
     
       9. The connector assembly of claim 8 wherein said upper header contact receiving means and preloading means includes a slot-like opening formed in said upper header cavity for receiving said arcuate contacting portion of said contacts, an opening formed in an upper portion of said upper header cavity for receiving said probe portion of said contacts, and a preloading ledge formed adjacent to said slot-like opening to cooperate with said preloading tab formed on said spring-beam portion of said contacts to controllably bias said spring-beam portion in a preloaded position when said upper header is fitted over said lower header. 
     
     
       10. The connector assembly of claim 8 wherein said lower header channel means comprises: a pair of substantially flat complementary channel portions formed within said lower header contact receiving cavity, each said channel receiving said base portion of one of said plurality of contacts;   a dog-leg shaped dielectric ridge formed between each complementary pair of channel portions to separate said pairs of complementary contacts; and   an opening for receiving said downwardly extending tail portion of said contact.   
     
     
       11. The connector assembly of claim 8 wherein said spring-beam portion of said contact is formed having a variable cross section. 
     
     
       12. The connector assembly of claim 10 wherein said pairs of complementary contacts are formed having their respective dog-leg portions offset from each other along each of their said bases such that said tail portions formed on said dog-leg portions project through said tail receiving openings formed in said pairs of channels formed in said lower header in a nonlinear manner with respect to each other. 
     
     
       13. A connector assembly for leadless integrated circuit packages comprising: (a) a plurality of complementary pairs of unitary metallic contacts, each of said contacts comprising: (i) an elongated S-shaped spring-beam portion;   (ii) an arcuate contacting portion formed on an upper part of said spring-beam;   (iii) a preloading tab formed on said upper part of said spring-beam adjacent said arcuate contacting area;   (iv) a substantially flat base portion connected to a lower part of said spring-beam portion;   (v) a dog-leg portion formed on said base portion;   (vi) a downwardly extending tail portion formed on said dog-leg portion;   (vii) a probe portion formed on said base portion;   (viii) a locating pin formed on said base portion, said complementary pairs of contacts differing solely in the location of said dog-leg portion formed on said base portion; and     (b) upper and lower dielectric headers each having a plurality of parallely disposed contact receiving cavities formed therein, said cavities separated by a plurality of intermeshing walls, each said cavity of said lower header including: a pair of substantially flat complementary channels formed within said lower header contact receiving cavity, each said channel receiving said base of one of said plurality of complementary contacts; an opening formed in a lower portion of each of said channels for receiving said contact locating pin; a dog-leg shaped dielectric ridge formed between each complementary pair of channels to separate and align said pair of complementary contacts; and an opening formed in each said channel for receiving said downwardly extending tail portion of said contacts; and   each said cavity of said upper header including: a slot-like opening formed in an upper portion of said upper header cavity for receiving said arcuate contacting portion of said contacts; an opening formed in an upper portion of said upper header cavity for receiving said probe portion of said contacts, and a preloading tab formed on said spring-beam portion of said contacts to controllably bias said spring-beam portion in a preloaded position when said upper header is fitted over said lower header.     
     
     
       14. The connector assembly of claim 13 wherein said spring-beam portion of said contact is formed having a variable cross section. 
     
     
       15. The connector assembly of claim 13 including means for mounting a leadless IC package on said connector assembly. 
     
     
       16. The connector assembly of claim 13 wherein said pairs of complementary contacts are arranged within said complementary pairs of channels such that said tail members project downwardly through said tail receiving openings in a staggered array. 
     
     
       17. The connector assembly of claim 13 wherein said contacts are vertically, edgewise aligned within their respective contact receiving cavities.